. >>> michael nutter, the president of the u.s. conference of mayors joining us from philadelphia. mr. mayor, thank you very much. >> thank you, andrea. >> you have been all over this issue, but now do you see an opening because of this horrendous tragedy to get people mobilized? >> andrea, i think the conversation has really shifted all across the country. i do believe that we've reached a tipping point here, and usually when you see that happen on any number of issues, different people are prepared possibly to take different action than maybe they were in the past. this is a horrific tragedy. it has really fwrached people in very, very different ways, and as saddened as we've always been about tucson or aurora, other places, and certainly death and carnage on our streets all across the cities of america, this particular incident, i think, is a culmination of a variety of these massacre type incidents that we've seen over the last few years, and they're increasingly happening. the issues of high capacity weapons, these magazines, assault weapons being used, body armor available out in the o
